Table 1.

Willingness to participate and provide self-report of immunization history.

Demographics		Invited to participate (N=706)
		Unwilling to participate	Provided self-report	P value
Total, n (%)		394 (56)	312 (44)	—a
Age (years), median (IQR)		33 (30-35)	32 (30-35)	.01
Language, n (%)
	English	326 (83)	247 (79)	Reference
	Spanish	13 (3)	12 (4)	.63
	Other	15 (4)	13 (4)	.73
	Unknown	40 (10)	40 (13)	—
Area-based socioeconomic status, n (%)
	Low poverty zip code	160 (41)	122 (39)	Reference
	Medium poverty zip code	97 (25)	60 (19)	.30
	High poverty zip code	137 (35)	130 (42)	.20

^aNot applicable.